Functional longevity of exposed geosynthetics

Abstract

The time at which a geosynthetic’s performance falls below established functional thresholds is known as the geosynthetic’s functional longevity. As opposed to “durability” which commonly refers to an individual exposure environment such as UV exposure or a specific chemical exposure preceded and followed by an index test to quantify physical changes, functional longevity is the result of the synergistic effects of one or more exposure environments happening simultaneously or sequentially preceded and followed by a performance test. Therefore, functional longevity is characterized by a “suite” of durability tests and an accompanying performance test. Exposed geosynthetics, such as rolled erosion control products (RECPs) and engineered turf are the most common candidates for functional longevity characterization. In each case, exposures can include ultraviolet radiation, biodegradation, and damaging mechanical forces. These exposures inevitably degrade the geosynthetic over time. Yet, the important question is, when do the synergistic effects of the simultaneous or sequential exposures degrade the geosynthetic to the point where its performance falls below established thresholds? This question can only be answered by putting the candidate product through a relevant series of durability and performance tests. This paper describes a series of durability and performance tests being used to characterize the functional longevity of RECPs.